A student measuring the focal length of convex lens by putting an object pin at a distance 'u' from the lens and measuring the distance 'v' of the image pin. The graph between 'u' and 'v' plotted by the student should look like

Options

A.
B.
C.
D.

Answer

C

Explanation

For a convex lens
`u=-ve f=+ve`
If `v=infty, u=f` and if `u=-infty, v=-f` .
We have `v=+ve` and `u=-ve`
and `u` and `v` are symmetrical. Hence graph is shown,